Source: MacRumors

Apple appears to be warning developers/distributers of an impending Quicktime update. The timing of which is simply limited to "the next few weeks".

Quicktime was most recently updated in January 2003, and simply provided general quality and performance enhancements.

Other sources (of unknown reliability) tie the Quicktime update with the iPod and iTunes updates which have been expected in the near future.

Of interest... in February, this article mentioned Apple, as well as other MPEG4 supports, pushing for Digital Rights Management (DRM) standards to be established for MPEG4.

MPEG-4's lack of DRM in comparison has meant that Apple had some way to go convince Hollywood executives that QuickTime and MPEG-4 are suitable methods of distributing movies.
Target date for establishment of this standard is said to be by June of this year. It is unknown if this will have any relation on this pending Quicktime update.

DRM could also have implications for Apple's distribution of AAC-encoded songs through their rumored music service.